You can try this:
(Using Richard's example):
aggregate(sdata['salary'], sdata[c('company')], function(x)tail(sort(x), 5))
On Thu, Sep 16, 2010 at 2:26 PM, Tan, Richard <[email protected]> wrote:
> Hi Richard
>
>
>
> Thanks for the suggestion, but I want top 5 salary for each company, not
> the whole list. I don't see how your way can work?
>
>
>
> Thanks,
>
> Richard
>
>
>
> From: RICHARD M. HEIBERGER [mailto:[email protected]]
> Sent: Thursday, September 16, 2010 11:53 AM
> To: Tan, Richard
> Cc: [email protected]
> Subject: Re: [R] get top n rows group by a column from a dataframe
>
>
>
> > tmp <- data.frame(matrix(rnorm(30), 10, 3,
> dimnames=list(letters[1:10],
> c("company", "person",
> "salary"))))
> > tmp
> company person salary
> a -1.04590176 -0.7841855 1.07150503
> b -1.06643101 0.6545647 0.43920454
> c 0.72894531 -1.3812867 0.41313659
> d -0.39265263 -0.3871271 0.69404325
> e 0.54028124 0.7124772 0.66630904
> f -1.46931714 -0.3823353 0.03069797
> g -0.33283666 -0.6351862 0.37920017
> h -0.79977129 0.2605315 0.92373900
> i 0.80614119 0.3727227 -1.16560563
> j 0.03165012 0.4690400 -0.81966285
> > order(tmp$person, decreasing=TRUE)[1:min(5, length(tmp$person))]
> [1] 5 2 10 9 8
> > tmp[order(tmp$person, decreasing=TRUE)[1:min(5, length(tmp$person))],]
> company person salary
> e 0.54028124 0.7124772 0.6663090
> b -1.06643101 0.6545647 0.4392045
> j 0.03165012 0.4690400 -0.8196628
> i 0.80614119 0.3727227 -1.1656056
> h -0.79977129 0.2605315 0.9237390
>
> You can easily write a function for that.
> top <- function(DF, varname, howmany) {}
>
>
> On Thu, Sep 16, 2010 at 11:39 AM, Tan, Richard <[email protected]>
> wrote:
>
> Hi, is there an R function like sql's TOP key word?
>
> I have a dataframe that has 3 columns: company, person, salary
>
> How do I get top 5 highest paid person for each company, and if
> I have
> fewer than 5 people for a company, just return all of them?
>
> Thanks,
>
> Richard
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
[[alternative HTML version deleted]]
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